Technology identifies lost colour at Roman Forum

Historical sources describe the menorah looted by the Romans when they destroyed the Second Temple in Jerusalem in A.D. 70 as made of gold, as God instructed Moses in Exodus.

The Arch of Titus in the Roman Forum [Credit: Yeshiva University Center for Israel Studies, via Unocad SRL]

So the recent discovery that a version of the menorah in a bas-relief on the first-century Arch of Titus in the Roman Forum was originally painted a rich yellow should not come as much of a surprise. But given that the image faded to the color of its underlying stone long ago — like so much else in and around the Forum — precise knowledge of its once-bright pigmentation comes as an exciting revelation to historians and archaeologists.

“The Bible said it was gold, but the monument, as it was seen for centuries, told us it was white,” said Steven Fine, the director of the Arch of Titus Digital Restoration Project and a professor of Jewish history at Yeshiva University in New York, which is sponsoring the project. “Isn’t it cool to be that much closer to the viewers of the first and second century?”

The findings were made possible using noninvasive spectrometry readings carried out on the arch this month.

“The advantage of this method is that it doesn’t harm the monument,” said Cinzia Conti, the state archaeologist responsible for the arch. The monument is not only an important part of Rome’s physical history but also “very significant for the Jewish community,” she said.

The arch, inaugurated in A.D. 81, has two interior reliefs that commemorate the Roman victory over Judea by Titus, a military commander and future emperor, and his father, the emperor Vespasian, a decade earlier. One relief shows Titus’ triumphal ride on a chariot, the other depicts a procession into Rome with loot from the temple, including the menorah as well as a sacred table and trumpets.

Professor Fine, who is the director of the Center for Israel Studies at Yeshiva, said that the menorah was a natural meeting ground for “both Jewish and Roman studies.”

The menorah, originally painted a rich yellow, on the Arch of Titus in the Roman Forum [Credit: Yeshiva University Center for Israel Studies, via Unocad SRL]

For Jews, he said, the Arch of Titus has been an emotional lightning rod for nearly two millenniums. The Jewish community in Rome is the oldest in Europe. “For centuries the Jews in Rome would not walk under it, as they saw themselves as exiles from Jerusalem forcibly brought to Rome,” Professor Fine said. “Then in the 19th century the arch became a marker of Jewish antiquity and pride, a symbol of exile and redemption that is so important to Jewish heritage.”

The arch’s menorah is thought to be the image used for the emblem of the State of Israel, though that hypothesis has been debated.

In recent years there has been a drive on the part of archaeologists and historians to discover the original colors of ancient statues and monuments, boosted by technical advances in the field. (Tests for color carried out on many of the monuments in the Forum in the 1980s that removed samples from the stone did not yield significant results.)

The latest generation of ultraviolet-visual absorption spectrometers are more manageable and more sensitive, “so we can get a reading analyzing a grain of pigment on a square centimeter, and that is very helpful,” said Heinrich Piening, a conservator with the State of Bavaria Department for the Conservation of Castles, Gardens and Lakes in Germany.

Mr. Piening did spectrometric readings on the arch and compared them with a database of pigments and dyes to identify the original color. The menorah, he said, was painted a particular yellow ocher “that would have looked like gold from far away.”

Ms. Conti said more tests would be carried out on the rest of the arch, depending on financing.

The spectrometric readings will also be used to fine-tune “Rome Reborn,” a 3-D model of ancient Rome developed by Bernard Frischer, a professor of art history and classics at the University of Virginia. “The Arch of Titus will be the first monument in ‘Rome Reborn’ that will have full restored color,” said Dr. Frischer, who was part of the team working on the monument. “But we still have another 10,000 buildings to color.”